My title of this blog may seem strange. Most people tend to lose their appetites for finger foods like sandwiches after looking and talking about feet, especially feet with bunions. I’m actually going to use the layered concept of a sandwich to explain why and how many bunions form.

What is a Bunion? A bunion is described as an enlargement of bone/tissue around the joint of the big toe. The medical term is “hallux abducto valgus deformity”, but commonly called a bunion. Bunions almost single handily keep podiatrist busy in this country. Yet, in third world countries where poor fitting shoes are not as common, bunions are not as common.

What Causes a Bunion? Although most people view bunions as a bone problem in the foot, in reality most bunions are truly caused by muscular imbalances in the foot. There are several layers of muscles in the foot, I like to use the analogy of sandwich when explaining the muscular foot layers and how imbalance between the layers can lead to a bunion. The first and third layers of foot muscles are the bread layers of the foot. The bread muscles (first and third layers) are called intrinsic muscles, meaning the muscles start and end in the foot and do not travel into the upper leg. These muscles hold the bones of the foot together and give it its shape (posture), just like the bread holds a sandwich together. The second layer of muscle are the long muscles of the foot, they actually start deep in the back of the leg and travel around the ankle and attach to the bottom of the foot. The long muscle of the second layer are very strong and help push our bodies trough locomotion, they are definitely the meat of the sandwich.

Problems occur when you try to make a sandwich without bread. Ponder this theoretical question, if you make a sandwich without bread, does it actually exist? (Enough with the Akins diet questions, I’m getting hungry) When the first and third layers of muscles that help stabilize the posture of the foot become week or inactive, the strong muscle of the second layer take over. There are two major long muscle that make up the second layer. One attaches to the tip of the big toe, and the other muscle’s tendon splits to attach to the bottom tips of the 4 small toes of the foot. When these long muscles become dominate in foot function, they cause hammer toes in the 4 smaller toes and a bunion in the big toe. (Hammer toes will be discussed in a future blog) Bunions usually form in 4 stages. The first stage may not be very observable, but if you test the strength and function of the intrinsic muscles of the foot (bread muscles) they will be very weak and the balance of the foot will be stable. Over a long period of time if the dysfunctional muscle imbalances are not corrected in the first stage, an actual shifting of the great toe will occur due to the pull of the Flexor Hallucis Longus (meat layer muscle that connects to the tip of the big toe, pointed above by the blue arrow). Because of the orientation of the muscle and its attachment site, it will cause the big toe to move laterally (over to the smaller toes). In a normally functioning foot several of the intrinsic muscles provide adequate opposition to this pull of Flexor Hallucis Longus (ying and yang relationship). But, when the short intrinsic postural muscles are weak and turned off, the long muscle of the foot will over-compensate and structural changes happen. The final and fourth stage is when the prolonged pull gets so great that the actual metatarsal (forefoot bone that connects to the base of the big toe) becomes wedged in the opposite direction, and TA-DHA, you have bunion.

Why do Bunions Occur? I believe the muscular imbalances that cause bunions occur from either natural causes or un-natural causes. Natural causes of poor foot function are due to injuries or improper foot development during childhood. In both of these scenarios over-pronation of the foot is the driving factor for the resulting muscular imbalance that causes the bunion formation. Technically, I might be more correct in saying the lack of mid foot supination in the propulsion phase of gait is the problem (meaning: the main arch of the foot does not raise during push off). The most common injury to the foot is an ankle sprain, which often leads to a tight rear foot that leads to an overly mobile midfoot and pronation issues. Developmentally, if a child starts to walk, say at the age of 6-8 months, their brains are often not ready to coordinate the muscle actions of the foot, leading to learned over-pronation. (P.S. the normal age for walking is 12 months) Finally, the un-natural causes of muscular imbalances in the foot are improper shoe wear. I believe there is no coincidence that 90% of bunions are diagnosed in women in industrialized countries. Narrow toed high heeled shoes are the main culprit. These shoes are a mechanical nightmare for your feet! (Again, I will spend a full blog on the mechanics of wearing high heel shoes.) How Can You Help? If you’re young and your balance is poor, or you are starting to see your big toe shifting, find a health care specialist who isn’t just going to tell you to wait a few years and then have surgery. Find an expert to give you a plan to restabilize your foot. If you sprain an ankle, don’t just walk it off, find someone with a strong background in sports medicine and get it checked out and properly rehabbed. Do not encourage your children or grandchildren to walk prematurely before they are ready. And if you are going to wear high heels, don’t walk in them!

Running is one of the most popular recreational sports in the United States. What I love about running is that it is a lifelong sport. Attend any local 5k race and you will see age ranges from 12 year olds to 80 year olds running the same race. It’s also a sport that doesn't require really fancy equipment to burn a lot of calories. (I have already discussed the main expense in running, shoes, in my previous blogs.) Another great thing about running is depending on your preference or your mood; you can run in groups or by yourself. With all of the great benefits of running, I find it interesting that runners rarely focus on technique or specific skill training for running. Maybe this is why over 1/2 of all runners injure themselves every year. At Team Chiropractic and Rehab of Ames, it is our goal to keep runners out of pain and prevent as many sports injuries as possible. It you want to become a good golfer, of course you would buy a set of clubs. But, often new golfers will pay for golf lessons. Actually, all ranges of golfers find it advantageous to hire a Pro to help them with their swing. Not only does coaching in golf make the golfer a better player, but it can help prevent injuries that occur with poor swing mechanics. For some reason, the idea of swing analysis for performance and injury prevention has not translated into the running community as much as the other recreational sports like golf. In this blog we will discuss one of the measurable aspects of the running gait, foot strike, and how effects performance and injury rate. (All of the information I’m going to share with you is very practical, however runners that have certain anatomical variances or injuries should consult a qualified health professional before trying to change their gait)

It All Starts At the Crash Zone: What I call the “crash zone” is the area of the foot that first contacts the ground while striding. The contact that a runner uses when their foot initially contacts the ground, determines their efficiency/speed, footwear selection, and their ability to absorb shock. Foot strike also directly relates to the susceptibly for most common running injuries: Shin Splints, Patellar tendonitis, IT Band Syndrome, Bursitis, Hamstring Tendonpathy, Plantar Fasciitis, Stress Fractures. There are basically three different ways to contact the ground when running:

Heel Strike- When the outside corner of the heel first impact the ground and then the foot rolls through to the mid and forefoot before toeing off. This type of impact mimics the foot contact while walking.

Midfoot Strike- When the first part of the foot that touches the ground is slightly behind the ball of the foot. After the initial contact, often the heel will briefly touch the ground before the gait cycle progresses to supination and the foot leaves the ground through toe off.

Forefoot strike- This is the classic “toe runner”. The first foot impact will be on or slightly in front of the ball of the foot. Rarely does the heel touch the ground with this type of running foot strike. Most sprinters use this contact; however there are people that use this type of contact to run long distances as well.

Running with a Flat Tire:

Imagine if you raced two identical cars of the exact same year and model, but one car had a flat tire. It is quite easy to guess which car would win in this race. If you look at the picture of the flat tire below, you can see the large distance between the center of mass over the axil and the tipping point of the wheel. The greater the distance the more energy it requires to keep the wheel rotating. The same goes with running form. Runners who heel strike will have a foot impact at greater distance from their center of mass then an individual who impacts on their midfoot or forefoot. Most heel strikers are what we term “over striders”. Over striding puts them at a disadvantage biomechanically to preserve their momentum by reaching their leg out further from their body to heel strike (running with a flat tire).

It may seem mathematically advantageous for the heel striker with the long over stride when running long distances. The longer the stride, the less steps they need to take, right? Wrong, this is the most common amateur running mistake. Stride length is not as important as stride rate in any form of human running (sprinting or distance). Let’s do the math to prove this point: Assume that a 5 foot tall individual wants to run a mile. Typically your jogging stride length is just below your height. Studies show that the average stride length for armature runners is only 120 strides per minute (spm). - A typical heel striker runner runs at 120 spm x 4.5 foot stride = 540 feet per min (just under 10 min mile)- A heel strike runner who really over strides at 120spm x 5 foot stride= 600 feet per min (9 min mile)- A mid or forefoot striker who has a shorter stride but a faster cadence can do 160spm x 4 foot stride= 640 feet per min (8:15 mile) You can see that even with a much shorter stride length, the faster cadence or stride rate, ran much faster than even the supper over strider. By the way, 160 spm is a realistic goal for most recreational runners. An elite professional runner usually has a stride rate of 180-200 spm.

Running with a Flat Tire While Stepping On the Breaks: Mathematically it should make sense why heel striking and over striding reduces running efficacy. But, anatomically and physiologically, heel strikers are at a disadvantage as well. By fully extending the leg to heel strike the runner does two things that put their bodies at a disadvantage (turn on the breaks). First, the extended heel striking leg has to fully lengthen the hamstring (the rear muscle to the leg). Weight lifters know that a long muscle is not a strong muscle. Running is all about elasticity in the muscle and tendons of the legs. When the muscle length is in a neutral position its tension to force relationship is at its maximum. However, when a hamstring is completely stretched out to because of the over striding, it loses a majority of its elastic springiness, leading to a slower cadence, more energy wasted by the muscle, and a decreased ability to absorb shock (can you say hamstring tear?). The second physiologic disadvantage of over striding is the body has to isolates muscle use. For example the quad (front leg muscle) has to fully contract to extend the leg fully to reach the heel contact. Verse in a midfoot strike the leg contacts the ground perpendicularly to the ground, letting both the hamstring and quad muscle function in a neutral length, which improves muscle elasticity and shock absorption.

There is one other disadvantage biomechanically to heel striking while running. To get the foot in a position to heel strike, the body needs to move up and down vertically more to let the heel travel over the ground before striking. This is a big waste of energy and increases the ground impact force on every stride. Usually the objective with running is to use our energy to move forward, not up and down. The best graph to visually explain the differences in force transmission in different foot striking patterns is below. If you notice the one big difference in the parabolic arcs is the sharp initial peak formed when the heal striker first impacts the ground. Imagine the arc of the graph was that of path of a pebble that you toss to someone. On the curve of the midfoot striker the curve was very controlled and smooth, therefore the pebble would be easy to catch. Imagine on the heal strike graph that we took the pebble and placed it in a sling shot and then fired it. That increased rate of force at the impact of heel strike is like the pebble traveling at a much faster rate and can cause injury when trying to catch it. If the rate of the impact force is too fast, the human body cannot “catch” or absorb the forces effectively, meaning the bones, tendons, ligaments and muscles are susceptible to injury.

How Do Shoes Fit In? Because most recreational runners have been exposed to high drop running shoes their whole lives, we have tricked our bodies into thinking it’s OK to hit the ground with our heels while running. I have discussed the reasons for this in my previous blogs on minimalist shoes and shoe fitting. It’s interesting how humans have been running for millions of years, yet within a few decades of wearing athletic shoes, many of us have completely forgotten how to run effectively and safely. If you want to make a change to running on your mid foot, find a shoe with a lower drop and a wide toe box to let your foot expand when running. However I do caution you that changing to a zero drop shoe “cold turkey” can be dangerous. Give your body time to transition to a new shoe, vary the shoes over the week and start with a hybrid shoe first before a full zero drop shoe. What about Forefoot Running: As I mentioned earlier, forefoot running is mostly done in sprinting. Running on the forefoot does lead to faster stride rates, but there are some distinct disadvantages to forefoot running for a long distance. First, just like heel striking, forefoot striking causes muscle to work in isolation and in shortened or elongated states. Forefoot strikers often have injury problems with their calf muscles because they have to contract and shorten during most of their gait cycles, leading to strains, tears and Achilles injuries. Also landing on the forefoot is not as stable as a midfoot strike (imagine running in high heel shoes). This instability will put the tendon and ligaments at risk (ankle sprains and Achilles tendonitis). Finally and not a big surprise, toe runners will have issues with stress fractures and injuries to their toes, the function of the four smaller toes is to help with balance, not to absorb shock on impact. How to Make a Foot Strike Change: Changing your gate is like learning to write with your non-dominant hand. You may have spent years running with a heel strike, it is imposable to change that overnight. I suggest a transition period of 2-3 months to make a gate change. First it take muscles several week to change in length, you can only expect injuries if you don’t let your body slowly adapt to the new running technique. Next there is the mental aspect of changing your form. Most people like to run because it lets them turn off their minds and relax. When you try to change your gait, you have to be consciously aware of every new movement your body makes. It will again take several weeks for this new running form to become reflexive or unconscious. I suggest in the beginning of the transformation, you only focus on form and technique for 1-2 minute periods during your run. For example after every mile, you focus on technique for an 1/8th of the next mile. Making the change to a midfoot strike is well worth the effort, you will be less susceptible to injury, and be a more efficient and faster runner!

Now, for the blog that everyone really wants to read, let’s talk about running shoes. In part 1 of the blog we thoroughly broke down the human foot and laid the foundation of how to evaluate your foot before buying a shoe. Now we need to look at the different parts of a shoe and how shoes can affect the way your foot functions. Hopefully, this blog will be able to streamline the elements of the shoe that really matter, and show you what aspects of a shoe don’t really matter and are just “Shoe Bling”. I want to thank JAX Outdoors for letting me use their shoes as demos in my community presentations and take pictures of them for this blog. If you have never been to JAX, it’s worth a trip to west Ames to check them out for any of your sporting good needs. When shopping for shoes, you need to have plan for finding the shoe that fits your needs as runner anatomically and functionally (learn more about your foot anatomy and biomechanics in Part 1). For example a runner with a mid-foot strike pattern with a history of ankle sprains that runs daily on cement needs different shoes then a person that only runs on tails, heel strikes, and under pronates. You always need to remember when shopping for shoes, that shoes are tools. Tools help us accomplish tasks more efficiently and help take stress off our bodies; shoes are the same way. But, when all you have is a hammer, and you need a screwdriver, problems will arise. In shoes, the wrong type of shoe can cause injuries and poor fitting shoes will wear out faster too. Shoes can also be used as tools to help change running technique or help protect an injury while it heals.

Shoe History: Humans have been walking on two feet for over 5 million years, but the earliest evidence of shoes only carbon dates back 10,000 years. Back then, primitive shoes where were worn to cover and insulate the feet from the elements. Athletic shoes have a very short history, about 100 years ago with development of rubber; companies like Goodyear started producing “sneakers”. It was not until 1970 that Phil Knight and Bill Bowerman began experimenting by pouring liquid rubber onto a waffle iron, that the modern day running shoe was developed. http://www.holabirdsports.com/running-tech-center/running-shoe-history.html Runners typically seem to develop a brand loyalty with shoe companies. Unfortunately this loyalty will get the runner into trouble eventually. Running shoe company's top engineers and executives are like NFL coaches. It seems like every year, half the NFL teams switch coaches and very few coaches now days spend their entire career with one team. The same thing is going on in the running shoe industry. If some new engineer comes up with a new shoe design for company X, Company Y will give the engineer a pay raise to quit and work for them and bring the new knowledge. So when this hot shot engineer takes his new job, he is going to change the design of your favorite shoe from company Y. If the companies are not loyal to you the consumer, you shouldn’t be loyal to them, just find the shoe that fits. Another little corporate secret is that most companies only use about 3 different molds to manufacture all of their shoes. Meaning, you are paying extra money for bright colors and “shoe bling” on shoes that have the exact same midsole and outer as the less expensive models.

Shoe Anatomy: Starting from the ground up, the part of the shoe that actually contacts the ground is the outsole and is made from a strong dense material. The next layer is the midsole and most of the flexibility and control of foot motion is controlled with in this layer. Typically it is formed from foam, many times different densities and stiffness of foam are used in areas of the shoe where motion of the foot needs to be slowed down. This is called a shoe with dual densities, there may be more than just two types of foam depending how much stability is needed. The layer contacting the foot is the insole, many times this is replaced by an insert or orthotic. An orthotic or athletic insert usually has some type of posting. A posting is anything (foam or plastic) that tries to limit pronation of the foot. Finally, there are the parts of the upper including the heal box, vamp, and toe box. An important measurement that should be addressed in all running shoes is the “drop”. Shoe drop is the delta or change in height from where the forefoot and mid foot are positioned off the ground compared to the rear foot. There are three basic types of shoes. Each one is designed for an ideal category of foot type. As we explained in Part 1, rarely does the shape of the foot (flat, neutral, high arched) match the actual function of the foot (over-pronated, neutral, and under-pronated). But, shoes are still basically broken down into 3 categories matching the 3 foot types: Cushion Shoes, Stability or Neutral Shoes, and Motion control Shoes. I will add four more categories to this discussion, they are: Minimalist, Hybrid, Toe spring, and Trail running shoes.

Cushion Shoe:-Purpose is to absorb large amounts of shock while not limiting foot movement.-Designed for the runner who under pronates.-Typically an under-pronator has a stiff foot, so they need a flexible shoe (many times there will be a break in the midsole between the rear foot and forefoot to promote increased shoe flexibility).-Have a curved sole to fit a high arched foot.

Neutral or Stability Shoe: -Propose to provide shock absorption and basic stability. -Designed for the ideal foot, or a person who wears orthotics. -A semi curved sole with moderate flexibility.-Theoretically, the most purchased running shoe.

Motion Control Shoe: Propose is to provide maximum stability and support of the foot that over pronates. Very dense, heavy, and thick foam is used in the midsole. The sole is almost straight and there is minimal motion when the shoe is twisted. (It should be noted that in several studies, every classification of runner who ran in motion controlled shoes had increased injury rates compared to other types of running shoe test. Please don’t release the Brooks Beast.)

Hybrid: Purpose is to bridge the gap between a cushion shoe and a minimalist shoe. A small drop, and high flexibility, light weight, while still providing some shock absorption. Example: Nike Free

Toe Spring: Purpose is to provide artificial big toe flexion and ankle dorsiflexion for individuals who lack those ranges of motion. A stiff sole with a large arched relief under the forefoot to rock over during gait.

Women’s Shoes: There are more than just color differences between male and female shoes. Anatomically and biomechanically, there are significant differences between men and women. Women have shorter legs (as a ratio of total height), wider hips, and more valgus alignment of the knees (“knock knees” or higher “Q” angle). When it comes to shoe fitting they often have more trouble finding shoes that fit well than their male counterparts. Women have triangular and narrower feet compared to males who have more square and wide feet. Their malleoli (ankle bones) are also lower. Women are also more likely to develop foot deformities such as bunions and need to be fit for shoes that provide adequate toe box room. Recommendations for Mid foot and Forefoot Strikers: I recommend a forefoot or mid foot striker wear a shoe with very little drop. Because a high heel/large drop shoe will cause a premature heel strike. This type of runner doesn't need excessive heel cushioning/motion control features, because pronation and shock absorption is basically over when their heel hits the ground. They are often better off with a hybrid or minimalist shoe style. These shoes offer adequate room in the toe box for increased widening of the forefoot on initial contact. If possible a flared heel cuff can be used to add support of the rear of the shoe during contact, taking strain off the Achilles tendon.

In the Shoe Store Tips · Weight it: heavy shoes usually provide more shock absorption and/or motion control, but they add weight that must be moved in every stride. · Twist it: does the mid foot flexibility match your foot type needs? · Bend it: does the forefoot bend where your big toe joint is placed within the shoe? · Poke it: are there dual density foams in the right areas for your needs? · Look at it: what is the curve in the sole like? How much of the shoe is “bling”? · Bring the socks you generally wear running to use while trying on the shoes. · Try on shoes later in the day or right after a run so your feet will have swelled. · Shoes should feel great when you put them on, don't buy them thinking you will "wear them in." · If you have wide or narrow feet, look for a brand that has multiple widths to fit your feet. · Find a different shoe if any part of your foot feels like it is rubbing · Do not shop when you are in a hurry. Be sure to walk/run around the store for a few minutes on a hard surface. · NEVER buy “seconds” shoes online, these shoes may save you $20 initially, but in the long term they can cost you much more if you are injured. The reason many shoes are sold at a discount online is that there is a manufacturing flaw within the shoe. Would you by a powertool or a car that had a mechanical defect? (In part 3, the last of the Shoes 101 blog, there will be a discussion about the cause of different running injuries and different shoe strategies to help heel and prevent future injuries)

The goal of these next blog posts is to remove some of the mystery of how to find the right running shoe for your specific foot. For the average consumer, shopping for a good pair of running shoes can be daunting. There are thousands of different models and styles of shoes to pick from. It doesn’t help that most costumers are influenced more by TV commercials about the shoe and how the shoe looks esthetically, than how it actually functions on their foot. I like to use the analogy that shopping for running shoes is like buying a $100 lotto ticket. It’s exciting when you are purchasing the ticket, but there is often buyer remorse when you get home and you realize the ticket was not a winner. Even more frustrating if you do find a winning ticket, you can never play the same numbers again because the shoe companies are always changing their shoe designs. Hopefully, after reading this blog, you stop feeling like you’re always playing the lotto at the shoe store, and your shoes always feel like a million dollars!

This blog will be 3 parts long. It will start by discussing what goes into a shoe first, that being your foot. The shoe must match your foot, not the other way around. Then in the second part, it will breakdown shoe anatomy and the different types of shoes and how they can help improve function and decreases injuries in runners. There will be a brief discussion in this part on running style/technique and the type of shoe that suits the runner (I will post more specific blogs on running form and technique in the future). Finally in the third part, I’ll post about several injuries that occur while running and how to prevent and aid in healing specific injuries with specific shoes.

Getting to know your own Foot:Humans started to walk bipedal (on two feet) anywhere from 5 million to 10 million years ago, depending on which archeologist you ask. The transition from ambulating on all fours to bipedalism may actually have been one of the most important evolutionary developments in mankind. There are two theories on why we started to walk up right. The first is that by walking only on our feet, we freed up our hands to use tools. The second idea, and most accepted theory is that by walking on two feet, human beings became more efficient. Ancient humans were able to walk/run for greater distances; which improved their ability to hunt. Bipedal man could literally chase his pray to death because of the improved efficiency. Maybe this why modern man still has the deep desire and love for running long distances?

To make the physiological change to bipedal locomotion, some major adaptions had to take place in the human body. First our posture changed to a more vertically erect posture, we developed a lumbar lordosis/mobile lumbar spine. The shape of our pelvis changed and many of the muscle of our pelvis had to change their function compared to other primates. I believe this is why so many injuries can be related back todysfunctional hips in modern man. Finally, our feet had to change in shape and function. We ask more out of our feet than any other animal on this planet. Our feet act as a stable platform for when we need to stand for hours, they act as the first line of shock absorption and they also transform into ridged levers when we need to push off in running.

The human foot is composed or 33 different joints and 26 bones. The structure of the foot articulations give the foot the ability to be very mobile and then stiffen depending on the position and contraction of muscles. Speaking of muscles, there are two types of muscles that attach to the foot, a short group called the “intrinsics”that are found within the foot, and then there are longer muscles that start at the leg bones (tibia/fibula) and then attach to the bones in the foot. The muscles and ligaments hold together the arches of the foot. Yes, I wrote arches, with an “s”. There are actually three different arches in the foot, the medial arch that most people think of when they think of a foot arch runs between the base of the big toe to the inner heel. The longitudinal arch runs along the outside of the foot, and the transverse arch runs across the forefoot. Together, these arches create a triangle or tripod within the foot. It doesn’t matter if you have really high arches or a “flat” foot; everyone needs to support themselves on the three points of the foot tripod. The most common deformity that occurs when there is a dysfunctional foot tripod is a bunion. When the tripod point at the base of the big toe becomes dysfunctional, the angle of progression changes when you walk (over pronation), forces are distributed unevenly, and muscles that usually anchored from that tripods point become weak. If this occurs over several years, the forefoot will widen and the joint of the big toe with start to deform.

As I mentioned previously, the foot needs to be a mobile shock absorber, for 5 million years humans walked barefoot on uneven terrain (it was not until the last few hundred years that humankind made everything flat with cement and concrete). This ability to keep the joints of the foot loose and adaptable is termed “pronation”. Pronation gets a bad rap; really, it is one of the most important motions in your foot. As a runner I would take a foot that slightly over pronates any day over a foot that doesn’t pronate enough. The motion of pronation is complicated when you breakdown the motion of every bone in the foot, but for the sake of simplicity, think of pronation as the foot “collapsing or rolling in”. Supination is the exact opposite of pronation, it is the mechanism of making the foot a “ridged lever”. As we walk or run, after we have adapted to the ground, absorbed the shock of impact through pronation, we transfer our body weight over and past our foot by pushing off through supination. It would not be very efficient to push off if the foot was still a “loose bag of bones” as it is in pronation. During supination, the muscles and tendons of the foot and leg bring the foot downward and inward, causing the bones of the foot to lock (windlass effect).

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Bio-mechanically, there are differences between running and walking. Walking can be described as a pendulum motion, where the rotation of the different parts of the body preserves momentum. In walking, the foot is in contact with the ground 60% of the time, and both feet are touching the ground simultaneously at different parts of the walking gait cycle to preserve the momentum used to propel walkers. Running uses principles more related to a spring. Running relies on the elasticity of the muscles and tendons to propel the runner forward. In contrast to walking, most of running is done in the air (40% foot ground contact time) and only one foot is ever in contact with the ground at one time. During running, pronation occurs during 70% of the ground contact period, and supination comprises the rest of the time the foot touches the ground. So what’s the big deal about “over pronation”? As stated previously, pronation is essential to human movement and actually helps prevent injuries then it causes. But, when pronation occurs at a speed or rate that your body can’t control, you can have complications that lead to injuries and decreased performance. I use a slingshot analogy to explain the concept of over pronation. I can pick up a pebble and toss it to someone; they will be able to catch it without difficulty because of the predicable slow speed of the toss. However, if I take that pebble and load it into a slingshot and fire it at someone, they will not be able to control and stop the pebble without some type of shield, or they will become injured. The shield in this analogy is a shoe or an orthotic that slows down the pronation. The worse type of over pronation is one that only happens in one foot, and not the other. In this case there is an asymmetry in the body that travels up the kinetic chain. (over pronation causes the lower leg to rotate in, the knee to twist down and in, the thigh rotate causing the pelvis to tip down and forward, leading to a curve in the lower back and a compensation in the middle back, dropping and rounding one of a shoulders).

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So what’s the big deal about “over pronation”? As stated previously, pronation is essential to human movement and actually helps prevent injuries then it causes. But, when pronation occurs at a speed or rate that your body can’t control, you can have complications that lead to injuries and decreased performance. I use a slingshot analogy to explain the concept of over pronation. I can pick up a pebble and toss it to someone; they will be able to catch it without difficulty because of the predicable slow speed of the toss. However, if I take that pebble and load it into a slingshot and fire it at someone, they will not be able to control and stop the pebble without some type of shield, or they will become injured. The shield in this analogy is a shoe or an orthotic that slows down the pronation. The worse type of over pronation is one that only happens in one foot, and not the other. In this case there is an asymmetry in the body that travels up the kinetic chain.

The best story of this relationship between the foot and rest of the body comes from baseball. In 1937, Dizzy Dean was pitching in an All-Star game. The batter hit a comebacker that hit Dean’s foot, fracturing his toe. While still nursing a sore foot, Dean resumed pitching. The soreness caused him to change his foot position and his pitching mechanics, leading to shoulder and arm problems. Dean was never able to overcome his shoulder injury, leading to his early retirement. His quote ““Fractured. Hell, the damn thing’s broken!”.

over pronation causes the lower leg to rotate in, the knee to twist down and in, the thigh rotate causing the pelvis to tip down and forward, leading to a curve in the lower back and a compensation in the middle back, dropping and rounding one of a shoulders (image produced by footlevelers)

Is There an Ideal Foot? Many people make the mistake of only looking at their foot when are trying to determine if they under or over pronate. The assumption is that if your foot is “flat” you must over pronate. This is a myth, if a person with a flat foot uses their foot tripod effectively, they may not have a pronation problem at all. Actually, a person with a flat foot can have a very stiff and ridged foot and may need a completely different type of shoe compared to what it looks like they should wear. The best example of this is the fastest man in world, Usain Bolt. Did you know he has flat feet? I don’t think I remember watching him run at the Olympics in heavy motion control shoes. Sadly many people with flat feet with normal foot mechanics are improperly fit into a motion control shoe or an orthotic. This causes them to complain the shoes are uncomfortable due to the artificial arch that presses into their underfoot. Actually, people with high arches that have very mobile and loose feet are more likely to become injured because their body can’t control the rate in which their foot collapses at a greater distance because of their high arch starting point.

Image from www.dukehealth.org

Much like the stereotyping of flat feet, there is an assumption that people with high arches need a cushion shoe because it is assumed that their foot is very stiff and they supinate more than they should. And the person with a “normal” looking arched feet (what ever normal is?) should be ok in a stability/neutral shoe. The moral of the story here is that looks can be deceiving. I can look at a door and assume I know how it moves, but until I physically open it, I never know if the door moves easily or is locked/jammed. The best way to tell how a foot moves is to have a professional palpate the motion of a foot and then analysis the foot when walking/running. Palpating your own foot or trying to self-analysis your gait can be tricky. The easiest way to tell about your foot tendencies during your gait cycle is to look at the wear pattern of an old pair of shoes. I call this “arch”eology (sorry it’s a lame pun).

The two other variables in foot function that become very important when fitting shoes are: 1. Where and how much your big toe bends in relation to the shoe. You may have never realized the ramifications that people have different sized toes, and the joints of the toes don’t always match where the shoe bends (can you say turftoe?). Typically in an athlete the big toe should bend up in the air 65 degrees when standing flat. There is also specific group of people that have a Morton’s foot, this is easy to distinguish because in a Morton’s foot the 2nd and maybe 3rd toes are longer then the first toe. This causes an alteration in toe off when they run and special attention needs to be paid in fitting them into a shoe that bends in the forefoot at the proper location. 2. How well your ankle flexes (dorisflexs) is also really, really, really important in runners and all other athletes. The number one reason we lose our ability to flex our feet are ankle sprains. If you severely sprain your ankle and never properly rehab after, the ligaments on the side and back of the foot scar down and you end up losing the ability to flex the ankle. In a runner ankle dorsiflexion should be between 20 and 30 degrees. Anything less will shorten the stride length and put excess stress on the soft tissues of the plantar fascia, Achilles tendon and the calf musculature.

The last point I’ll make before we start to break down shoes in the next blog, is that there are these things called legs that attach to your feet. In an ideal world there would never be anything wrong with the legs above the feet that could cause concern about shoe fit and function. But, we live in the real world, not an ideal world. For example, if people have knees that are bowed out or knocked in, special consideration needs to be made in shoe choice. Sometimes function may call for one type of shoe, but that shoe will not work with the individual because the shoe makes a condition in the knees or hip/back worse. This is when compensation needs to be made in shoe choice and professional help should be sought out.